Time Zone change for San Luis, Argentina

Mariano Absatz - El Baby baby at baby.com.ar
Mon Mar 16 22:10:17 UTC 2009


Jesper is right in what he notes regarding the inconsistency of 2nd 
Saturday @24:00 vs. 2nd Sunday @00:00.

It is weird that, even when San Luis is having its own timezone for the 
winter, they also have their own algorithm for changing... in their 
favor, the National Government is NOT defining in advance what algorithm 
they will use next year, so that they could decide every year a 
different rule :-(


please, if you can contact someone responsible within the Provincial 
Government, try to explain to them the problem and what would they do in 
April 2012 that is the first time the rule will fail (I bet they'll say 
that they will eventually check that in 2011 or later)... don't expect 
them to understand the problem (although it might be easier that someone 
does understand in San Luis than in Buenos Aires).

Don't hesitate to write directly to me in Spanish if you'd rather I 
translate or forward your messages to the list, either at this address 
or, better yet, at "el PUNTO baby ARROBA gmail PUNTO com".

If you need help, drop me a line in private and we can talk over the phone.

Regards, and very nice to see there's someone else in Argentina worrying 
about this :-)

Olson, Arthur David (NIH/NCI) [E] escribió el 16/03/09 16:19:
> I'm forwarding this message from NorbertoNazabal, who is not on the time zone mailing list. Those of you who are on the list, please direct replies appropriately.
> 				--ado
> From: Norberto Nazabal [mailto:nazabal at gmail.com] 
> Sent: Monday, March 16, 2009 3:19
> To: Jesper Nørgaard
> Cc: TZ-list
> Subject: Re: Time Zone change for San Luis, Argentina
> Hi Jesper,
> Thanks for you answer, I want to let you know that currently we are using the GMT-4 time zone here at San Luis, since the last Sunday 15th at 00:00.
> I checked the Chile DST and I think we will use the same time zone, but I will try to contact to somebody in the goverment to confirm that information.
> Thanks for your notes about the consistency issues and I hope the new time zone for San Luis can be added to your database after the confirmation of which time zone we will use.
> Regards,
> Norberto Nazabal.
> 2009/3/16 Jesper Nørgaard <jnorgard at prodigy.net.mx>
> Norberto Nazabal wrote:
>> Basically the law says:
>> 1) We will use the time zone GMT-3 from the 0 hour of the second Sunday of October to the 24 hours of the second Saturday of April.
>> 2) We will use the time zone GMT-4 from the 0 hour of the second Sunday of April to the 24 hours of the second Saturday of October.
> I agree that this is an accurate translation of the document which was published already back in December 2008. However this definition contains serious problems of consistency. And not only that, if this was published so long back (2-3 months) why was it not followed in 2009, but rather following the Chile DST and Buenos Aires Argentinian DST instead with a frantic press conference the Thursday before the weekend when it was implemented?
> The problem of consistency is the perhaps not obvious fact that the Second Saturday of a month at 24:00 is *not* always the same time as the Second Sunday at 0:00 of a month. Thus the above definition is not always defining two contiguous periods (DST and non-DST) as one might think. I am sure this is an attempt to give an intuitive definition where one period goes to the 24:00 hours of one day, and is replaced with a new period starting at 0:00 hour the next day, but it fails. The first problem will occur in 2012 where the Second Saturday is 14.th. of April while the Second Sunday is the 8.th. of April (e.g. the problem occurs when the first in the month is a Sunday). So literally the definition will have it that GMT-3 will be followed from 2011-10-09 00:00:00 to 2012-04-14 24:00:00 and GMT-4 will be followed from 2012-04-08 00:00:00 : During a week we have both GMT-3 and GMT-4 ??
> The most probable scenarios are that either San Luis redefines the decree in a consistent way, or that either Chile DST or Argentina DST is followed. The future will tell. Already in October 2009 the two latter are different, Chile starts DST 2009-10-11 00:00:00 and Buenos Aires starts DST 2009-10-18 00:00:00.
> Regards, Jesper Nørgaard Welen

Mariano Absatz - "El Baby"
baby at baby.com.ar

Clarke's Fourth Law: For every expert there is an equal and
opposite expert.
  Arthur C. Clarke, 1999
  English physicist & science fiction author (1917 - 2008)
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